The invention resides in a mounting arrangement for hard metal cutting blades in cutting heads for working wood or plastic materials.
Cutting heads for working wood or plastic materials are provided with exchangeable cutting blades of a hard metal. The cutting blades are clamped in position in corresponding recesses at the circumference of the cutting head body between a support plate and a clamping member. The support plate abuts, with its back surface, a support surface in the cutting head base body and extends radially beyond the circumference of the cutting head so as to support the cutting blade essentially over the whole surface area thereof. The clamping member is biased, by means of a tightening screw, against the front side of the cutting blade so as to firmly engage the cutting blade with the front side of the support plate.
To permit multiple sharpening of the cutting blade by grinding of its cutting edge, the blade must be supported so as to be radially adjustable. At the same time, it must be securely supported so as to prevent radial movement thereof or its radial expulsion at high operating speeds of the cutting head. It is therefore common practice to provide, at the backside of the cutting blade and at the front side of the support plate, complementary tooth profiles which fit into each other in several radial positions so that, when clamped in position, the cutting blade is engaged with the support plate in a form-fitting manner. The support plate is generally connected to the base body in a particular position by way of locking pins.
Another arrangement is shown for example in DE 92 13 466 V1. Here, a support plate is provided at its front side with teeth which engage a corresponding opposite profile at the backside of the cutting blade and the support plate is provided at its backside also with a tooth profile which cooperates with a corresponding tooth structure in the support surface of the base body.
It is furthermore known from DE GM 1693811 to provide for a form-locking radial engagement of the cutting blade by engaging tooth structures wherein the clamping member is provided with a tooth structure which is in engagement with a tooth structure provided at the front side of a tooth plate which is connected to the cutting blade by pins. A support plate is not provided in the cutting head disclosed in this publication.
The cooperation between the tooth profile structures on the cutting blade and on the support plate is critical to some degree since the radial play should be as small as possible in order to avoid engagement position errors of the cutting blade and since the cutting blade and the support plate need to be fully and tightly engaged with each other when mounted on the cutting head in order to prevent breakage of the cutting blade which is relatively brittle.
It is the object of the invention to provide a mounting arrangement for mounting hard metal cutting blades in cutting heads which provides for firm engagement of the cutting heads while reducing the chances of breakage.